Heat-pressure operated warning switch



23, M. L. MICHAELSON 2,454,283

HEAT-PRESSURE OPERATED WARNING SWITCH Filed Nov. 9, 1945 I 5 I i I Ill/11111, jlllllllll! g PRESSURE TEMPERA TURE Figzl I N V EN TOR. MARIO/V L. MICHAELSON BY wzzwz {1mm A TTORNE Y5 Patented Nov. 23, 1948 UNITED STATES "PATENT OFFICE.

amended'April 30, 1928; 370 O. G. 757) The invention described herein may be manuiactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates generally to signalling 5 mettallic msmtaer I is supported by insulating su means, and more particularly to signalling means por mem er and is connected to the dependfor indicating excessive changes in temperature ing contact member 8 by an electric ond t and/or pressure ina closed fluid sysatcigmi d Eefiher elclll.i The giepelnding contabct member 9 All devices of this character, m e n accor spos n an nsu ating mom er I in the once with the teachings of the prior art, and 10 top of the cap member l2. The cap the groundwith which I am familiar, have been operated ed by ground wire l5. The contact member 9 is in direct proportion to the pressure of the fluid in an electrical circuit which comprises wire IS, in the system fort 1theirl ogeratettlil onla cdhangf of izrsdgcating iliwiretm, battery h2g9 31d wire temperature 0 e u n e c ose sys em. 0 groun safe y cap mem r is dis- Such systems have a relief valve so that steam is posed in the housing to permit escape of fluid escapes ilrlllen a? certiiint pressure i h upon aln excessivle1 increase of pressure to prevent y of 8 B d M a or sys ems on au omoan exp as on. T e diaphragm 2 is at ground pobfles hav a tliisermgrsltatic tswitch twhich'lopeg fi v tjential while contact members 6 on the bimea Warn ng 11gb 011 81115 r'llmen P e58 tallic member 'I and contact member 9 are at warnin lights usually operate o y on changes in the potential of the battery i9. This is true when tgmplilrature slndtgrolgiifofii is no i lgliysen if a 022;: contlact member 6 does not touch contact mems on occur in e ne. no war. 1 18 13 in the s n Systems when there is In operation, when the pressure in the sysa ea ,tem increases, such as when a head gasket in an It IS. acc y, an Object of y invention to internal combustion engine leaks, allowing com- OVeIOOme the abflve and'othel" f in bustion gases to enter the fluid system, the dias mem er 0 engage e con ac mem r eregalggfigg 1252211:cigprilysgngengionefropgrgggg 2g inergizinl a a icilclilt from ground 21 to wire atte wre indicati 1i ht l1, ir and/or pressure changes in a closed system, which is, contgt member 9 g i f is simple in construction, economical in cost, ef- Shaped member 3, diaphragm zvcap member '2, g l g g iggigi economical in manufacture wire 15 to ground, thereby energizing the light a a s of my to e that: tiiiiliiftl iffiti ytiii i'f: means in a fluid system which gives a wringing comes excessive, bimetallic member 1 will move upon an 9 Ve ncrease n pressure an /O upwardly and the contact member 6 will engage tenoigigtlgcts of my inve will became the contact member 4. The indicating light I! dent from the following detailed description, 40 Wu again be energized by elierglzauon of the t ken in conjunction with the accompanying circuit from the ground 2i, wire 213, battery I9, diawmgs m which, wire 18, indicating light I'l, Wire I6, contact mem- Figure 1 is a vertical cross sectional view of s'hconductor 5x 2 g g T my novel warning system, and a'ped mam t d ap agm cap I wire Figure 2 is a graphic representation illustratto groundthe limits of Operation of my device It will thus be seen that a warning will be Referring now to the drawings Figure 1 shows given that isbest illustrated bythe diagram shown a housing I separated by a diaphragm 2, a por- 1115181118 Awarnme Willbe given-3 tion of the housing below the diaphragm being When the fluid in the system is confined in a closed fluid system such as a sealed cooling a a temperature pon i t point 0 5 system for an internal combustion engine of an reached. 7 automobile. A generally U-shaped member 3 is 2. When the fluid is not confined due to a leak disposed on the diaphragm '2 and has contact in the system and the temperature reaches member 4 in one side thereof and an insulating point 2. member 5 on the inside of the bottom portion 3. When a cylinder head gasket leaks, allow- 2 thereoi'. A contact member 6 on a bimetallic element 1 of any suitable metal engages the contact member 4 upon an excessive increase of temperature of the fluid in the system. The biing combustion gases to enter the fluid system and thus forcing the pressure above point if.

It will be evident that my novel warning system will beoperative under a. change in either pressure or temperature or both, and a leak in the system will,not negative the operation of my novel indicating means.

Various changes may be made in the specificembodiment of my invention without departing from the spirit thereof or from the scope of the appended claims.

What I claim is:

1. In a warning system employing a warning indicator actuated by the closing or an electrical circuit for indicating an excessive increase in pressure and/or temperature of fluid in a closed fluid system, a unitary switch automatically closing said electrical circuit upon a predetermined increase in pressure and/or temperature of said fluid, said switch comprising a housing, a diaphragm extending across the interior ofsaid housing, said housing on one side of said diaphragm being in communication with said fluid system, a generally U-shaped supporting member on the opposite side of said diaphragm, a contact member on one of the legs of said generally U-shaped supporting member, a bimetallic member extending between thelegs of said generally U-shaped supporting member, a second contact member in said housing spaced from said first mentioned contact member and from the same side of said diaphragm, and an electrical conductor between said bimetallic member and said second contact member, said bimetallic member being engageable with said first mentioned contact member to close said electrical circuit upon a predetermined increase in temperature of the fluid in said fluid system, and said first mentioned contact member being'engageable with said second contact member to close said electrical circuit upon a predetermined increase in pressure of the fluid in said fluid system.

2. In a warning system employing a warning indicator actuated by the closing oi'an electrical circuit for indicating an excessive increase in pressure and/or temperature of fluid in a closed fluid system, the switch as set forth in claim 1, wherein said bimetallic member and said second contact member are insulated from said 5 housing. and said bimetallic member is further insulated from the other of the legs of said generally U-shaped supporting member.

3. A unitary switch responsive to a predetermined increase in pressure and/or temperature of fluid in a closed fluid system for'automatic closing of an electrical circuit actuating a warning indicator, said switch comprising a housing, a diaphragm in said housing, said housing having an opening opposite one side of said diaphragm for communication with said fluid in said closed fluid system, a bimetallic member in said housing adjacent the opposite side of said diaphragm, said bimetallic member being insulated from said housing and said diaphragm, a first contact member :supported by said diaphragm and engageable by said bimetallic member upon a predetermined increase in tempera- ,ture, a second contact member in said housing insulated therefrom and spaced from said first contact member, said second contact member being engageable by said first contact member on flexing of said diaphragm, and an electrical conductor between said bimetallic member and said second contact member. 7, o

4. A switch as set forth in claim 3 connectable in an electrical circuit at said second contact member and at a point on said housing.

MARION L. MICHAEL-SON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENT Number Name Date 49,907 Baker Apr. 21, 187% 1,102,998 Coleman July 7, 1914; 1,270,928 Coesfeld July 2, 1918 2,351,408 De Beaumont June 13, 1944 

